A newly-released analysis conducted by the International Research Institute for Climate and Society showed sea surface temperatures in the east-central Pacific were near the borderline of weak El Niño levels… and atmospheric variables near neutral in mid-January. The report also indicated the likelihood of seeing sea surface temperatures in the equatorial Pacific returning to neutral conditions by spring.
So what does this mean for our weather here in Central Texas? And what exactly is an El Niño / La Niña?
ENSO: what is it?
The El Niño Southern Oscillation (ENSO) is defined as “one of the most important climate phenomena on Earth” due to its ability to change the global atmospheric circulation, influencing both temperatures and precipitation across the world. ENSO is a combination of changes in both the ocean and atmosphere. There are three phases to ENSO: El Niño, La Niña and neutral. These phases can act as indicators of what conditions (warmer/drier or cooler/wetter) we could see in the winter.
El Niño and La Niña events:
— Tend to develop April – June
— Tend to reach their maximum strength during October – February
— Typically persist for 9-12 months, though occasionally persisting for up to 2 years
— Typically recur every 2 to 7 years
El Niño conditions are marked by warmer than average (+0.5°C) sea surface temperatures in the central and eastern equatorial Pacific. It’s also characterized by a weakening or reversal of normal easterly winds (east to west wind) along the equator. This typically leads to cooler and wetter conditions in Central Texas.
It’s important to note that every El Niño plays out differently, with no one event the same.
La Niña conditions are marked by cooler than average (-0.5°C) sea surface temperatures in the equatorial Pacific and stronger than normal easterly winds along the equator. This typically leads to a warmer and drier pattern in Central Texas.
Neutral conditions of ENSO are in place when one of these two occur:
— sea surface temperatures are near average (between +0.5°C and -0.5°C of normal)
— the ocean temps and atmospheric circulation are not coupled (ex. warmer than normal sea surface temps but no change in winds)
The mentioned report breaks down the probability of El Niño, La Niña and/or neutral conditions forming in the overlapping seasons of 2020. Listed below are those probabilities:
NOTE: the season abbreviations indicate 3 month increments. Example: “JFM” = January, February, March… “FMA” = February, March, April… “MAM” = March, April, May… etc.
2020 FORECAST: Given current oceanic and atmospheric data, probabilities favor neutral conditions for the foreseeable future of 2020 (equal chances of warmer/cooler and wetter/drier conditions).
Fore more information on ENSO: El Niño Southern Oscillation, click here.